1. Field of the Invention
The present invention relates generally to liquid thermal management systems that thermally manage heat producing devices and more specifically it relates to a liquid thermal management purging system for efficiently removing the liquid coolant within a liquid thermal management system prior to opening the system for maintenance.
2. Description of the Related Art
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
Modern electronic devices (e.g. microprocessors, circuit boards and power supplies) and other heat producing devices have significant thermal management requirements. Conventional dry thermal management technology (e.g. forced air convection using fans and heat sinks) simply is not capable of efficiently thermally managing modern electronics.
Single-phase liquid thermal management systems (e.g. liquid cold plates) and multi-phase liquid thermal management systems (e.g. spray cooling, pool boiling, flow boiling, jet impingement cooling, falling-film cooling, parallel forced convection, curved channel cooling and capillary pumped loops) have been in use for years for thermally managing various types of heat producing devices.
Spray cooling technology is being adopted today as the most efficient option for thermally managing electronic systems. U.S. Pat. No. 5,220,804 entitled High Heat Flux Evaporative Spray Cooling to Tilton et al. describes the earlier versions of spray technology, as it relates to cooling electronics. U.S. Pat. No. 6,108,201 entitled Fluid Control Apparatus and Method for Spray Cooling to Tilton et al. also describes the usage of spray technology to cool a printed circuit board.
The liquid coolant typically used within a spray cooling system is a dielectric fluid (e.g. perfluorocarbons and hydrofluoroethers) having a low vaporization temperature at standard atmospheric pressure. One common brand of dielectric liquid coolant for two-phase thermal management systems is a perfluorocarbon manufactured by Minnesota Mining and Manufacturing Company (3M®) under the federally registered trademark FLUORINERT®. Unfortunately, perfluorocarbons have relatively high global warming potentials (GWP). For example, the perfluorocarbon PF-5070 (manufactured by 3M) has a GWP exceeding 5,000 (100-yr-ITH).